package com.md.lession3;

import java.util.Scanner;

public class Circle {

	public static void main(String[] args) {
		
		Scanner scan = new Scanner (System.in);
		
		double radius;
		
		System.out.println("请输入圆的半径(cm):");
		radius = scan.nextDouble();
		
		double area;
		area = radius * radius * 3.14 ;
		
		System.out.println("圆的面积为(cm²):"+area);
		


	}

}
